The example circuit in Figure 10-77 will be used to
illustrate the idea of voltage drop. It is important to
differentiate between voltage and voltage drop when
discussing series circuits. Voltage drop refers to the
loss in electrical pressure or emf caused by forcing
electrons through a resistor. Because there are two
resistors in the example, there will be separate voltage
drops. Each drop is associated with each individual
resistor. The amount of electrical pressure required to
force a given number of electrons through a resistance
is proportional to the size of the resistor.

In Figure 10-77, the values used to illustrate the idea
of voltage drop are:

Current, I = 1mA
R1 = 1 k O
R2 = 3 k O
R3 = 5 k O

The voltage drop across each resistor will be calculated
using Ohmís law. The drop for each resistor is
the product of each resistance and the total current in
the circuit. Keep in mind that the same current flows
through series resistor.